Gamification: facilitating a gradual return-to-play

Professional athletes depend on a speedy recovery from sports injuries or surgery because their livelihood depends on their physical fitness. Returning to competition too soon after injury can have negative health consequences. Standard tests are now combined with virtual reality to determine the optimal time to return to play.

In this MEDICA-tradefair.com interview, Dr. Markus Wenning and Jonas Weber describe a joint project of the Albert Ludwig University of Freiburg and the EXXETA Company. They reveal the drawbacks of the standard RTP process and explain how VR can improve it.

What is the typical return-to-play protocol?

Markus Wenning: The return-to-play process is generally tied to a battery of tests. You should follow the gradual steps of rehabilitation and subsequent approval for certain training contents. Based on the test results, the athletes can then progress in rehabilitation. The first step after surgery is to return to a normal gait. This is followed by the start of running training and a run test. After successful completion, athletes perform the hop test cluster, followed by other functional testing. This is ideally a systematic battery of tests that includes force plate testing, running, and hopping tests. These tests are used to document and plan the recovery progress and facilitate return-to-play permission. In competitive and professional sports, testing is carried out in a motion and sports performance laboratory with biomechanical analysis and force plates, if possible.

You have now coupled these tests with virtual reality. How does this support or improve the RTP process?

Wenning: The drawback of standard tests is that they are predictable for a professional athlete. Athletes know exactly what to do and at what point. They can plan their actions because they intimately know the testing environment. However, these tests poorly reflect what happens later in the field. Once the athletes leave the lab and encounter their opponents or a piece of equipment, they can no longer plan their movement patterns. They are suddenly confronted with more complex situations that necessitate reactive responses, which is not adequately reflected in the current series of tests.

Jonas Weber: We decided to change up these predefined process steps by integrating random and unexpected game situations or problems into these tests via virtual reality. This prevents the athlete from knowing ahead of time where to move and how to react. Our first step was to connect the Vicon System - an optical motion capture system that doctors use for this type of testing in the lab - to the VR application. It allows us to capture full-body performance and all data thanks to the VR system, which is not possible as such with standard consumer hardware. With the latter, you usually only see the access controller and the head. This significantly intensifies immersion, the condition in which the user loses awareness of the fact that they are actually in a virtual world. We used this as a foundation to complete the first test runs and analyzed the obstacle navigation responses.

What have been your experiences so far?

Wenning: The test users expressly notice the gaming aspect of the experience. The feedback so far indicated that activities in the virtual world are fun, motivating, and interesting. That's important to us, although the factual benefit in a scientific context is given priority. The VR setting also adds a level of surprise and uncertainty to the movements. This could prove beneficial for our purposes because we believe that the element of uncertainty will be reflected in particular movement patterns that a professional athlete would otherwise not experience in predefined, unchanging environments. This might potentially uncover faulty and pathological movement patterns – those being movements that are associated with an increased risk of injury.

What are the drawbacks? Can motion sickness affect the results for example?

Weber: Motion sickness obviously can have an impact, although it definitely plays a lesser role when it comes to full-body tracking. Virtual reality sickness (VR motion sickness) is the physical discomfort that occurs when a user's brain receives conflicting signals about self-movement in a digital environment. In reality, he or she sits on a chair and is actually not moving. However, if my full body is engaged in the virtual world and I can move around the room, the same way I would in the real world, it immensely reduces symptoms of motion sickness. Latency in VR devices (a lag or delay in response) is one potential problem in this context. The athletes make rapid movements and the technology may have a delayed response. These fast movements might cause an issue for the hardware. VR headsets tend to be rather bulky devices and may need to be adjusted to prevent them from falling off the athlete’s head the moment he or she jumps.

What is the current status of the project?

Wenning: Our setup works, but we want to scientifically review how much value we can add with VR testing. To do this, we compare the results of the standard battery of tests with those from the VR tests. Our goal is to identify the specific changes in movements in the VR setting.

EXXETA develops various sport-specific scenarios that are implemented in the VR context. All athletes complete the same series of tests in reality and in the virtual setting for rehabilitation purposes. Before resuming competition or team training, athletes also perform sport-specific testing with the VR system, which entails reactive, complex scenarios. In the long run, the battery of tests might become more than just a purely scientific instrument. We aim to develop a tool that is both fun and adds medical value. Our next goal is to establish virtual reality tests as a regular laboratory at the University Medical Center. To fund this, we are applying for a research grant from the German Federal Institute of Sports Science.